The present invention relates to a power work-machine such as a chain saw.
In general, a power work-machine, such as a chain saw, has an arrangement whereby a driving force from an engine, such as a two-cycle internal combustion engine, is transmitted through a centrifugal clutch to, for example, a chain sprocket for driving a saw chain, so that the saw chain is driven to perform work such as the work of cutting trees. Sometimes, while a power work-machine such as a chain saw serves as a power unit, a work-machine attachment designed for another type of work, such as a hedge trimmer, drill, blower or mower, is attached to the main body of the work-machine. In this case, the work-machine is used in work other than the work it is inherently designed for. In this way, multi-purpose use of a power work-machine is possible. However, some problems are encountered with conventional power work-machines. For instance, the mechanism for transmitting power from the engine of the power unit to the driving section of the attachment tends to be complicated, or fails to achieve positive transmission of power. Therefore, there have been demands for power work-machines possessing high serviceability.